This is a trial in patients with operable adenocarcinoma of the rectum. It seeks to compare the worth of seven cycles of 5-FU + leucovorin (LV) and radiotherapy (RTX), where the first three cycles are given preoperatively and the remaining four postoperatively, to seven cycles of FU-LV and RTX given postoperatively. Postoperative high-dose radiotherapy has been shown in randomized and nonrandomized studies to significantly decrease the rates of local recurrence in rectal cancer. No significant improvement has been demonstrated, however, in disease-free survival and in overall survival. Postoperative chemotherapy alone has been found to increase the disease-free survival and has demonstrated borderline survival benefit. The combination of both has been evaluated in several prospective trials. An indication of benefit in both reduction of local recurrence and improvement in disease-free survival and survival has been demonstrated. Results from large-scale trials currently in progress will provide definitive answers regarding the worth of the combined regimen.